code: def chat_response():
      return {
          "candidates": [
              {
                  "author": "1",
                  "content": "Hi there! How can I help you today?",
              }
          ],
          "messages": [{"author": "0", "content": "hi"}],
      }
  
file_path: mlflow/tests/gateway/providers/test_palm.py
imports: from unittest import mock
  import pytest
  from aiohttp import ClientTimeout
  from fastapi import HTTPException
  from fastapi.encoders import jsonable_encoder
  from pydantic import ValidationError
  from mlflow.gateway.config import RouteConfig
  from mlflow.gateway.constants import MLFLOW_GATEWAY_ROUTE_TIMEOUT_SECONDS
  from mlflow.gateway.providers.palm import PaLMProvider
  from mlflow.gateway.schemas import chat, completions, embeddings
  from tests.gateway.tools import MockAsyncResponse
label_desc: Use image node_id 4 for calling a global function with example usage: chat_response() and returns: dict